This invention is directed generally to clothes dryers, and more particularly, to safety systems for clothes dryers.
Conventional clothes dryers are constructed of a tumbler configured to hold clothes, a motor for rotating the tumbler, a heating element for heating air, a fan for blowing the heated air across the clothes while the clothes are in the tumbler, and an exhaust conduit for venting the heated air from the dryer. The heating element may be electric or gas powered. Because a close dryer includes a heating element, there always exists the chance of fire. Conventional clothes dryers include many different safety devices for reducing the likelihood of a fire. For instance, a conventional clothes dryer often includes a lint screen for removing lint from the air coming from a tumbler. The lint screen is often placed in an easily accessible location, such as in a slot in a top surface of the clothes dryer, and covers an exhaust conduit where the conduit leaves the tumbler. The lint screen collects lint from the air that has been picked up from the clothing in the tumbler. Most, if not all, manufacturers of clothes dryers recommend that lint screens be cleaned after each load of clothes is dried. Otherwise, an unacceptable amount of lint may build up on the lint screen and pose a fire hazard and prevent efficient operation.
Clothes dryers also typically contain heat sensors, such as thermocouples, for preventing dryers from overheating and causing fires. Most clothes dryers position a thermocouple proximate to a heating element of the clothes dryer. In this position, the thermocouple is capable of monitoring the area surrounding the heating element and can be used to determine whether the air surrounding the heating element is exceeding a predetermined threshold temperature. If the air becomes too hot, the thermocouple breaks a circuit, which thereby turns the dryer off and prevents the dryer from operating. The temperature of the air surrounding the heating element is monitored because the air surrounding the heating element often becomes too hot for safe operation when an exhaust conduit contains a blockage. Blockages in the exhaust conduits are dangerous because the blockages can cause the heating element to overheat and ignite lint near the heating element.
Many exhaust hoses for clothes dryers are incorrectly installed such that the exhaust hoses have internal diameters that are too small or are restrained. Such configurations accelerate lint collection on inside surfaces of the exhaust hoses, which may eventually result in partial or total blockage of the exhaust conduit. Such accumulation of lint may occur relatively quickly or over a longer period, such as a few years, and may go unnoticed by a homeowner. Such conditions are extremely dangerous.
While the conventional configuration of locating a thermocouple proximate to heating elements in a dryer has undoubtedly prevented many fires, dryers having this configuration remain susceptible to fires. In fact, dryers remain one of the most dangerous household appliances. Thus, a need exists for a system for improving the safety of clothes dryers.
This invention relates to a restriction sensor system usable with a clothes dryer for identifying blockages in an exhaust conduit downstream of a lint screen in an effort to prevent dangerous conditions and fires. The blockages may be found in the exhaust conduit located inside of or outside of a clothes dryer. The restriction sensor system may include a pressure sensing device for sensing the air pressure in an exhaust conduit of a clothes dryer downstream of a lint screen and creating an alert message when the air pressure on the exhaust conduit exceeds a pre-established threshold air pressure. The pressure sensing device may be formed from a body configured to be coupled to an exhaust conduit of a clothes dryer and may have at least one cavity for containing a diaphragm. The pressure sensing device may also include a diaphragm capable of reacting to relatively small changes in air pressure in the exhaust conduit. The pressure sensing device may also include a sensor for sensing the reactions of the diaphragm. In one embodiment, the sensor may be coupled to the diaphragm. The pressure sensing device may also include an orifice in the body for admitting a gas, such as air, from the exhaust conduit into the cavity of the pressure sensing device.
The restriction sensor system may also include one or more indicators for indicating that the pressure sensing device has identified that the air pressure in the exhaust conduit of the clothes dryer has exceeded a threshold air pressure. The indicator may be capable of generating a visual alert or an audible alert, or both. The indicator may be configured to be attached to a control panel of a clothes dryer or in another location on a clothes dryer.